ML20086J254

AO 74-23:on 741112,recirculation Loop Sample Inboard Isolation Valve AO-39 Did Not Indicate Full Close During Surveillance Testing.Caused by Full Close Limit Switch Failing Initially

ML20086J254
Person / Time
Site:	Peach Bottom
Issue date:	11/22/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-74-23, NUDOCS 8401230518
Download: ML20086J254 (2)

Text

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.s, PHILADELPHI A ELECTRIC COMPANY

, 'i 2301 M ARKET STREET ;3

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PHILADELPHI A. PA.19101 . . CI,1

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November 22, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Di rectorate of Licensing Washington, D.C. 20545 3 ear Mr. Giambusso:

Subject:

Abnormal Occurrence The fo11cwing occurrence was reported to Mr. Wal t Baunack, A.E.C. Region 1 Regulatory Operations Office on November 13, 1974.

Written notification was made to Mr. James P. O'Reilly, Region- I Regulatory Operations Office on November 13, 1974 In accordance with Section 6.7.2.A of the Technical Specifications, Appendix A of OPR-56 for Uni t' 3 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence:

Reference:

License "urner DPR-56 Technical Specification Reference 3 7.D Report No.: 50-278-74-23 Report Date: November 22, 1974 Occurrence Date: Novemoer 12, 1974 Faci li ty: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 Identi fication of Occurrence:

Recirculation Loop Sample Inboard Isolation Valve A0-39 did not indicate full closed during surveil ?ance testing; further testing showed that the valve . leaks through when in the closed position.

Conditions Prior to Occurrence:

Plant at normal operating conditions -- approximately 73% power.

8401230518 741122 gDRADOCM 05000278 PDR 12072 7w COPY SENT REGION

. Nosember 22, 1974 Page 2 o O

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, Desc~riotion of Occurrence: .

During routine surveillance testing of the PCIS Logic System, A0-39 failed to indicate full closed on an isolation signal. The full open indicating light extinguished, but the full closed light did not light. While attempting to verify valve closure by sample flow indication, i t was discovered that A0-39 leaks through while in the closed position.

Desicnation of Accarent Cause of Occurrence:

The valve was stroked several times from the control switch, and it then indicated properly. The full closed limi t swi tch apparently failed to operate initially, but af ter valve exercise it performed sa ti s fac tori l y.

Analysis of Occurrence:

Af ter testing, A0-39 indicated proper stroking. .Since the valve did not provide a tight shutoff of the sample line, the out-board isolation valve, A0 LO, was placed in the isolation condi tion and a tight shutoff was achieved as indicated by cessation of sample flow.

Corrective Action:

Corrective maintenance wi11 be performed on this valve when plant condi tions permi t.

As~ required by the Technical Specification, a daily log of the operable isolation valve position was immediately instituted in the form of an established surveillance test which verifies that the position of the operable isolation valve, in the same line, is in the close or isolated position.

Failure Data:

None Previous.

Very truly yours,

/L, ej I ' ',l lun Li /.

ti.,J. Cooney Ass' t Gen'1 Superintendent G,eneration Division cc: fir. J. P. O 'Rei lly .

Director, Region 1 Uni ted States Atomic Energy Commission 631 Park Avenue King of Prussia, PA 19406' b______ ' ' '

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